A film inspection device is equipped with a first fixed roll, a second fixed roll, a first moving roll, and a second moving roll. The first and second fixed rolls stretch an electrolyte film, which includes a part that is irradiated with light between first and second driving rolls, from one surface side thereof. The first moving roll stretches the electrolyte film from the other surface side thereof. The second moving roll stretches the electrolyte film from the other surface side thereof. The second moving roll is moved such that a conveyance path of the electrolyte film between the second driving roll and the second fixed roll becomes short, while the first moving roll is moved such that the conveyance path of the electrolyte film between the first driving roll and the first fixed roll becomes long.